1. Field of the Invention
The present invention relates to an image-processing device that reads image data optically by use of an image-reading unit such as a scanner from a document, and records the image data read by the image-reading unit on recoding paper by use of an image-recording unit such as a printer. The present invention particularly relates to an image-processing device, a method to process an image, and a record medium for efficiently correcting density of image data at an image-reading unit, the density of the image data at an image-recording unit and the density of the image data controlled by a density notch.
2. Description of the Related Art
A device that includes an image-reading unit such as a copy machine, a scanner and a facsimile is commonly used recently. A device that includes an image-recording unit such as a printer is also commonly used. In addition, a composite device that includes a plurality of devices such as a copy machine, a scanner, a facsimile and a printer has been placed on the market. The above-described devices adopt various methods to correct density of an image. For instance, a method to correct density characteristics of image data that depend on the image-reading unit by widening signal levels of the image data that is read from a document by the image-reading unit is referred to as input-density correction. A method to correct density of image data in an electrical area by increasing and decreasing the density by an operation using a density notch is referred to as notch-density correction. A method to correct density of image data by adjusting settings of the image-recording unit is referred to as recording-density correction.
For instance, Japanese Laid-Open Patent Application No. 9-224155 discloses an image-processing device that includes a plurality of density-conversion methods to convert density of image data to a digital signal by applying several data-conversion methods, and a method to select one of the density-conversion methods according to detection of density distribution of the image data. This conventional technology is adapted to the above-described input-density correction so that the image-processing device can easily execute density correction on various types of documents such as a document wherein texture density of the document is high, a document wherein texts are written in low density, a graph on a graph sheet, a photograph and a drawing. However, units and methods that execute the input-density correction and the notch-density correction are combined together in the above-described image-processing device, and thus a user cannot control each of the input-density correction and the notch-density correction separately. Additionally, the user cannot control the recording-density correction individually in the above-described image-processing device.
Accordingly, the image-processing device can only execute the input-density correction at its image-reading unit, but cannot execute the notch-density correction and the recording-density correction separately so that a high-quality output image may not be obtained by the above-described image-processing device. For instance, when a composite device whereto the above-described conventional technology is adapted executes a printer function, image data that has not been processed through the image-reading unit is supplied from an external application to the image-recording unit where the image data is recorded on recording paper, and thus the input-density correction on the image data at the image-reading unit is not executed. Additionally, when the composite device executes an image-copying function, stains are removed from the texture of image data read by the image-reading unit by executing the input-density correction at the image-reading unit. However, there is a case that an output image may not be a desirable one by light-emitting characteristics of the image-recording unit since the recording-density correction cannot be adjusted independently by a user.
Accordingly, it is a significant issue to efficiently execute the above-described input-density correction, notch-density correction and recording-density correction. In other words, it is a significant issue to optimize density correction in an image-processing device such as a copy machine, a scanner, a facsimile, a printer and a composite device.